The video of Imbonerakure militia members follows a recent video in which they encouraged the rape and impregnation of opposition supporters.

Burundi has been plagued by deadly political violence since President Pierre Nkurunziza successfully sought a disputed third term in 2015. Hundreds have been killed and hundreds of thousands have fled the country.

Lawyer and activist Lambert Nigarura told The Associated Press that the latest hate messages are meant to depict ethnic Tutsi as bad people, and he called it "the final step in preparation of genocide." He urged the international community to take action against Imbonerakure activities in schools.

The latest video was filmed by local human rights group iBurundi. It shows Imbonerakure members singing with schoolchildren in the local Kirundi language, saying their president in 1993 was assassinated in cold blood. Melchior Ndadaye was Burundi's first ethnic Hutu president, and the country's Tutsi-led army was blamed for killing him.

In the video, the Imbonerakure asks whether those who killed the president have stopped the killings, and the children reply that the killers have not stopped and they know them well.

Burundi has faced similar tensions between Hutu and Tutsi as neighboring Rwanda, where the 1994 genocide left more than 800,000 Tutsi and moderate Hutu dead. What sparked it was hate speech against the Tutsi minority spread by Hutu extremists.

In Burundi, ruling party members have called the Imbonerakure peaceful. But Human Rights Watch earlier this year reported that Imbonerakure members had brutally killed, tortured and severely beaten scores of people across the country.